Craft CMS stores arbitrary content provided by unauthenticated users in session files
CISA confirms exploitation of this vulnerability in real attacks. Prioritise checking whether your application is affected. CISA KEV · CC0 1.0
Craft CMS stores arbitrary content provided by unauthenticated users in session files. This content could be accessed and executed, possibly using an independent vulnerability. Craft CMS redirects requests that require authentication to the login page and generates a session file on the server at /var/lib/php/sessions. Such session files are named sess_[session_value], where [session_value] is provided to the client in a Set-Cookie response header. Craft CMS stores the return URL requested by the client without sanitizing parameters. Consequently, an unauthenticated client can introduce arbitrary values, such as PHP code, to a known local file location on the server. Craft CMS versions 5.7.5 and 4.15.3 have been released to address this issue.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | craftcms/cms | >= 5.0.0-alpha.1, < 5.7.5, < 4.15.3 | 5.7.5, 4.15.3 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-35939
- https://github.com/craftcms/cms/pull/17220
- https://github.com/craftcms/cms/commit/e4c7bac8f31010aee048409f9ef6f744a83146b2
- https://github.com/craftcms/cms
- https://github.com/craftcms/cms/releases/tag/4.15.3
- https://github.com/craftcms/cms/releases/tag/5.7.5
- https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-25-147-01.json
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-35939
- https://www.cve.org/CVERecord?id=CVE-2025-35939
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:H- Weakness (CWE)
CWE-472- Platform
- Composer
- Package
craftcms/cms- Disclosed
- 08.05.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-7vrx-9684-xrf2 - CC BY 4.0
Vulnerability history: craftcms/cms
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 127
- First → latest
- 07.2021 08.2026
- Without a fix
- 6
- Exploited in attacks
- 4
Severity breakdown
- Critical 9
- High 41
- Medium 65
- Low 12
Disclosures per year
- 2021: 3
- 2022: 22
- 2023: 13
- 2024: 9
- 2025: 6
- 2026: 74
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Craft CMS stores arbitrary content provided by unauthenticated users in session files this entry
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